1. Field of the Invention
This invention relates to infrared (IR) scanners and, more specifically, to oscillating type IR scanners.
2. Brief Description of the Prior Art
The purpose of a scanner of the type discussed hereinbelow is to sweep in azimuth a two-dimensional infrared scene across a one-dimensional array of detectors, thus creating a two-dimensional image of the scanned scene with the infrared scanning system. This is accomplished by precisely controlling the position of a mirror which scans the scene in synchronization with the sampling of the detector. Conversely, this process may be viewed as sweeping the column of detectors across the field of view. Some scanners can also hold a static position (i.e., not scanning). An interlacer can be provided which moves in elevation in the cross-scan axis up and down one half of a detector pixel distance to scan between the prior positions of adjacent detector elements and increase the vertical resolution of the system.
The main performance attributes of an IR scanner are linearity, repeatability and efficiency. Historically, polygon scanners have had a greater advantage over the oscillating scanners in terms of linearity and repeatability performance. However, the low scan efficiency plus added power, weight and size of a polygon scanner renders it unsuitable for deployment in some systems.
Prior art galvanometer based scanners have been incapable of providing the linearity and repeatability required for focal plane array (FPA) base imaging systems.